1. Field of the Invention
The present invention relates to a bending angle detector which detects a bending angle of an articulation portion of a person, and also relates to an electronic musical instrument employing it.
2. Prior Art
As known well, a non-electronic musical instrument generates a sound by striking a string, a key or by blowing in general. Most of the electronic musical instruments generate a sound by playing a keyboard attached thereto.
If a musical tone can be generated in accordance with a natural motion of a person, it may be possible to perform the music, regardless of the playing technique required for the conventional musical instrument. If so, it is possible to take the new pleasure in the musical performance or it is possible to obtain a brand-new performance effect. However, the conventional musical instrument cannot be performed, regardless of the playing technique. For this reason, there is a strong demand to develop a new electronic musical instrument.
Meanwhile, a bending motion of the articulation portion of the person, such as his fingers, wrist, elbow and shoulder is a general and natural motion of the person, which is frequently used in a dancing. Therefore, if the musical tone can be controlled based on such motion of the person, it may be possible to control the musical tone, regardless of the playing technique.
In order to satisfy the above-mentioned demand, the present applicant has proposed a new type of the electronic musical instrument which can control the musical tone in response to the bending motion of the person's hand, leg etc., which is disclosed in Japanese Patent Laid-Open Publication No. 1-167891. FIGS. 1A, 1B show a construction of a bending angle detector which is used to detect the bending angle of the articulation portion of the person in the electronic musical instrument. In FIGS. 1A, 1B, casings 1, 2 are fixed at respective positions along a finger such that the finger articulation will be located between them. In addition, resistor plates 3, 4 are provided in the casings 1, 2 respectively. Further, a sliding plate 5 is movably provided between the casings 1, 2 such that brushes attached to both edges thereof are in contact with the resistor plates 3, 4 respectively. When the finger is bent as shown in FIGS. 1A, 1B, a distance between the casings 1, 2 along the finger is elongated, so that the brushes of the sliding plate 5 move on the resistor plates 3, 4 respectively. In this case, the brushes and resistor plates 3, 4 function as a linear-slide-type variable resistor. Thus, the resistance will be varied in accordance with the movement of the brush to be moved on the resistor plate. Based on the resistance variation, the bending angle of the finger is detected.
The above-mentioned bending angle detector is constructed such that two casings must be fixed at respective positions at both sides of the finger articulation. Therefore, there is a drawback in that it is troublesome for the person to attach and remove the detector, or such construction of the detector prevents the smooth motion of the finger. Further, due to the movable construction of the detector in which both edges of the sliding plate 5 must be slid on the resistor plates 3, 4, there is another drawback in that scale, width and weight of the detector must be inevitably enlarged.